WASHINGTON — In signing off on steep steel and aluminum tariffs, President Donald Trump could be striking deep at the heart of Texas.

He formalized on Thursday new import levies of 25 percent on steel and 10 percent on aluminum — saying the U.S. has "not been treated fairly by other countries" — in spite of concerns from Texas Republicans and business leaders that it would harm consumers and the economy at large.

"A strong steel and aluminum industry is vital to our national security," said Trump, flanked by steelworkers at a White House signing ceremony. "Steel is steel. You don't have steel, you don't have a country."

The worry in Texas may be tempered by Trump's decision to allow initial exemptions for Canada and Mexico, and perhaps other U.S. allies down the road. The White House has also played down any possible negative effects from the tariffs as "fake news."

But the Lone Star State remains in a precarious spot, particularly amid continued fears of rising costs and a potential trade war.

Texas leads all states in the amount of steel and aluminum it imports. A much greater share of Texans work in the energy sector and other industries that rely upon steel and aluminum than in those that actually produce the metals.

And the state's globalized economy could be susceptible to any retaliation from abroad.

"I hope he's right and I'm wrong. But my read of history is that I don't know any winners in a trade war," Rep. Jeb Hensarling, R-Dallas, said on Bloomberg TV. "Trade is not a zero-sum game."

.@POTUS: "We have to protect and build our steel and aluminum industries, while at the same time showing great flexibility and cooperation toward those that are really friends of ours both on a trade basis and a military basis." pic.twitter.com/8403ZJm27v

The U.S. steel and aluminum industries welcomed the tariffs, announcing plans to reopen plants and hire more workers thanks to the trade action.

"We hope the era of American trade surrender is coming to an end," said Scott Paul, president of the Alliance for American Manufacturing.

The import levies, which have divided Trump's Cabinet, are slated to go into effect in 15 days.

The measure will also include some flexibility. Canada and Mexico will be initially excluded as they continue to engage the U.S. in North American Free Trade Agreement renegotiations. Other countries will have an opportunity to make their case for similar concessions.

"I'll have a right to go up or down depending on the country and I'll have a right to drop out countries or add countries," said Trump, who earned plaudits from some Democrats for his effort.

President Donald Trump holds up the "Section 232 Proclamation" on aluminum imports that he signed during Thursday's ceremony with steel and aluminum workers, Vice President Mike Pence, Treasury Secretary Steven Mnuchin and Commerce Secretary Wilbur Ross (right) in the White House.

(Chip Somodevilla/Getty Images)

That tit for tat would be certain to hit Texas, the nation's export leader. And Texas Republicans helped lead the campaign to dissuade Trump.

At the forefront has been Rep. Kevin Brady, a Republican from The Woodlands who leads the House Ways and Means Committee. He organized more than 100 Republicans — nearly 20 from Texas — to write the president this week with "deep concern" about "broad, global tariffs."

Brady praised Trump on Thursday for including some exemptions but urged the "White House to go further to narrow these tariffs."

"So they hit the intended target — and not U.S. workers, businesses and families," he said.